One of my responsibilities over the years has been to field questions from our members and authorities having jurisdiction (AHJs) to help them find and understand code requirements. I have benefitted from the process as well. As a member of numerous technical committees for the National Fire Protection Association (NFPA), assisting members and AHJs provides valuable feedback to propose changes for rewritten and clarified code language, which cuts down on misinterpretations. Fewer misinterpretations means less time spent on each job, which improves profitability. I believe good communications among the stakeholders is one of the most important factors to providing a reliable fire protection system. Here is an issue that regularly arises. 


Must I connect duct detectors to a fire alarm control unit that is installed to monitor a fire sprinkler system?


There has always been plenty of confusion about this. The 2007 edition of NFPA 72 added new language and definitions to help clear things up. 


The new definition for “Dedicated Function Fire Alarm System” states: ”A protected premises fire alarm system installed specifically to perform fire safety function(s) where a building fire alarm system is not required.” 


A definition for “Dedicated Function Fire Alarm Control Unit” was also added: “A protected premises fire alarm control unit which is intended to provide operation of a specifically identified fire safety function, such as sprinkler alarm and supervisory control unit or an elevator recall control and supervisory control unit.”


In the Protected Premises chapter, a new section was added for Dedicated Function Fire Alarm Systems. It states: “In facilities without a building fire alarm system, a dedicated function fire alarm system shall be permitted and shall not be required to include other functions or features of a building fire alarm system.”


The intent is to make it clear that, when a fire alarm control is provided to meet a specific need (monitoring a fire sprinkler system or elevator smoke detectors), you are not required to connect other equipment that normally would be connected to a building fire alarm system, such as duct detectors, kitchen hood systems or notification appliances. Please note that the smoke detector required to be installed over the fire alarm control unit and the single manual fire alarm box are still mandatory. The smoke detector is required to preserve the fire alarm signal in case of fire when the control unit is in an area that is not constantly attended. The manual pull station is required to provide a backup means to transmit a fire alarm signal when other automatic initiating devices connected to the system are down for repair or test.


Seems clear enough, right? Well, in recent conversations, I found it may not be as clear as we thought. One AHJ stated that NFPA 90A, Standard for the Installation of HVAC Equipment, states: “In addition to the requirements of 6.4.3, where an approved fire alarm system is installed in a building, the smoke detectors required by the provisions of Section 6.4 shall be connected to the fire alarm system in accordance with the requirements of NFPA 72, National Fire Alarm and Signaling Code.” His argument is that a fire alarm system was installed, and it was approved for installation; therefore, the duct detectors must be connected to the fire alarm system even if it was only intended to monitor the fire sprinkler system. It would be much better if the word “approved” was changed to “required.”


Another AHJ made the same argument about connecting kitchen-hood systems based on language in NFPA 17. Both referred to the NFPA 72 definition for “Fire Alarm System” and didn’t go to any subdefinition to better define the usage.


You are very likely to encounter situations like this on an upcoming job, and you probably have encountered them in the past. Depending on the AHJ, you may have had to connect the duct detectors to the fire alarm panel. 


Another huge issue that arises from this misinterpretation is that the AHJ now also wants horns and strobes added to the system. Pretty soon you have a full-blown fire alarm system installed. Not only does it cost more, but the ongoing inspection and testing requirements will be added expenses for the owner. Remember, the only code requirement in a case such as this is that a fire sprinkler system was required and that system needed to be monitored. Period.


We all need to work toward clearer language in the codes. This will help everyone involved—designers, installers, AHJs and owners. I will write about more issues like this in upcoming columns. 


If you have a code interpretation issue to share, please contact me. I believe we can all learn from the past experiences of others and should share this information with readers.